The start of the 2011 season has been filled with surprises, particularly in terms of blown saves. The Chicago White Sox and St. Louis Cardinals’ bullpens have been especially unpredictable recently. Here’s the latest:

White Sox

The White Sox’s bullpen is a mess. Matt Thornton has blown all four of his save opportunities thus far, and has allowed 11 runs (five earned) on 12 hits in 5.2 innings.

Chris Sale has the team’s only save, but when given the chance to close the door last Wednesday, he allowed three runs on three hits without recording an out. He hasn’t pitched since.

Jesse Crain could be a ninth inning option, having allowed just two runs in 8.1 innings thus far with a 10/2 K/BB ratio.

The best pitcher in Chicago’s pen, however, has been 27-year-old Sergio Santos. The former first round pick has recorded 8.2 scoreless innings in six appearances this season, striking out 11 while walking four. He probably isn’t the best long term option, but if the White Sox were presented with a save opportunity tonight, he’d likely get the nod. He’s currently owned in just 18 percent of Yahoo! leagues.

Cardinals

Ryan Franklin blew his fourth save opportunity in five tries on Sunday, and now sports an 11.57 ERA through six appearances (4.2 innings).

Jordan Walden has converted two save opportunities since being named the Angels’ closer last week. Through 8.1 scoreless innings this season, Walden has allowed just three hits. He’s struck out 10 and walked four. He’s currently owned in 74 percent of Yahoo! leagues.

Twins

After blowing two consecutive save opportunities, Joe Nathan was removed from the Twins’ ninth-inning role. Despite converting his first three saves, Nathan’s velocity is down (average fastball of 93.6 mph in 2009, 91.2 mph in 2011). Likewise, he’s issued five free passes in 5.1 innings.

Matt Capps has converted the last two save opportunities for the Twins, but he hasn’t exactly been perfect. Through 10 innings, Capps has allowed five runs on eight hits. He has yet to walk a batter, however. Capps has closer experience (111 career saves), but one would think it’s only a matter of time before Nathan is pitching in the ninth again.

Here are the latest injury updates:

David Aardsma is expected to begin a rehab assignment tonight at Triple-A. He will be asked to make three or four appearances, meaning he could return to Seattle by the end of the month.

The Blue Jays activated Frank Francisco from the DL on Tuesday. Jon Rauch has done an admirable job in Francisco’s absence (6.2 innings, two runs, two walks, five strikeouts, three saves), but will likely relinquish the ninth inning duties soon.

Andrew Bailey continues to progress towards a rehab assignment, but the A’s have not yet released a timetable for his return. It’s possible he could be back by late-April or early-May, but Brian Fuentes will continue to close games until then.

Here’s a full closer/setup man list. The most fluid situations worthy of a close eye are highlighted in bold.